• Korean Journal of Microbiology
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• v.31 no.1
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• pp.54-62
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• 1993

Intracellular adenosine deaminase (ADA) from Aspergillus oryzae was purified using ammonium sulfate fractionation, a DEAE-Sephadex A-50 anion exchange chromatography, an ultrafiltration using a PM 10 membrane and two times of Sephadex G-100 gel filtration chromatography. The enzyme was purified 151 fold with a 9% recovery. Purified enzyme gave a single protein band with a molecular weight of 105,000 delton. The enzyme was reasonably stable. The enzyme activity was kept even after 1 hr incubation at 55.deg.C, but decreased significantly at 60.deg.C. The pH optimum was found to be from 6.5 to 7.5. Among tested compounds, the substrate activity was found with adenosine, adenine arainofuranoside, formymcin A, 2'-deoxyadenosine, 3'-deoxyadenosine, 2', 3'-isopropylidene adenosine, 2,6-diaminopurine deoxyriboside, .betha.-nicotinamide adenine dinucleotide (reduced form), 6-chloropurine riboside, 2'-adenine monophosphate (AMP), 3'-AMP and 5'-AMP. The values of Km of adenosine and 2'-deoxyadenosine were calculated to be 500 and .$710\mu$m, respectively. ADA was sensitivite to $Zn^{2+}$, $^Cu{2+}$ and $Fe^{3+}$, p-chloromercuribenzoate and mersalyl acid inactivated the enzyme. The activity of enzyme was not changed when ADA was incubated with dithiothreititol, 2-mercaptoethanol, N-ethylmaleimide, iodoacetic acid and iodoacetamide.

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.139-146
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• 2000

7- Bromomethylbenz[a]anthracene is a known mutagen and carcinogen. The two major DNA adducts produced by this carcinogen, i.e., $N^2$-(benz[a]anthracen-7-yl methyl)-2'-deoxyguanosine (2, b[a]$a^2$G) and $N^6$-(benz[a]anthracen-7-ylmethyl)-2'-deoxyadenosine (4, b[a]$a^6$/A), as wel 1 as the simpler benzylated analogs,$N^2$-benzyl-2'deoxyguanosine (1, $bn^2$G) and $N^6$-benzyl-2'-deoxyadenosine (3, $bn^6$/A), were prepared by direct aralkylation of 2'-deoxyguanosine and 2'-deoxyadenosine. To determine the site-specific mutagenicity of these bulky exocyclic amino-substituted adducts, the suitably protected nucleosides were incorporated into 16-base oligodeoxyribonucleotides in place of a normal guanine or adenine residues which respectively are part of the ATG initiation codon for the lac Z' \alpha-complementation gene by using an in situ activation approach and automated phosphite triester synthetic methods. The base composition and the incorporation of the bulky adducts into synthetic oligonucleotides were characterized after purification of the modified oligonucleotides by enzymatic digestion and HPLC analysis.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.243-248
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• 2004

As diverse synthetic precursors of cyclic adenosine diphosphate ribose (cADPR), several adenosine derivatives in which azido or amino group is introduced at 2'- or 3'-position of the sugar moiety of adenosine were prepared from readily available adenosine via conventional protocols. These synthetic sequence employs very efficient reactions conditions that proceed at or below ambient temperature with actual yields of >80% for each individual step.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.365.3-366
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• 2002

New and improved preparations of structurally modified nucleosides are important goals in synthetic organic chemistry because of the potential utility of these compounds as synthetic precursors of many biologically active molecules in cells. In our program to synthesize the bioactive nucleosides, such as AdoHcy hydrolase inhibitors and cyclic adenosine diphosphoribose(cADPR) analogues. (omitted)

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1134-1138
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• 2007

Cordycepin (3'-deoxyadenosine) is an adenosine analog, isolated from Cordyceps militaris, and it has been used as an anticancer and anti-inflammation ingredient in traditional Chinese medicine. We investigated the effects of cordycepin (3'-deoxyadenosine) on human platelet aggregation, which was induced by thapsigargin, a tumor promoter, and determined the cytosolic free $Ca^{2+}$ levels ($[Ca^{2+}]_i$) (an aggregation-stimulating molecule) and cyclic-guanosine monophosphate (cGMP) (an aggregation-inhibiting molecule). Cordycepin inhibited thapsigargin-induced platelet aggregation in a dose-dependent manner, and it clearly reduced the levels of $[Ca^{2+}]_i$, which was increased by thapsigargin ($1\;{\mu}M$) or U46619 ($3\;{\mu}M$). Cordycepin also increased the thapsigargin-reduced cGMP levels. Accordingly, our data demonstrated that cordycepin may have a beneficial effect on platelet aggregation-mediated thrombotic diseases through the $[Ca^{2+}]_i$-regulating system such as cGMP.

• Korean Journal of Microbiology
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• v.41 no.3
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• pp.236-238
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• 2005

The effect of light on production of cordycepin (3'-deoxyadenosine) was investigated using Cordyceps militaris. Among Cordyceps spp. tested, C. militaris KCTC 6064 was the best for cordycepin production, After 120-hr cultivation of C. militaris KCTC 6064 at $24^{\circ}C$ in YMG broth with light (1,000 lux), 51.6 mg/l of cordycepin was produced. In general, production of cordycepin with light illumination was better than that without light. Cordycepin production under light illumination was enhanced up 96-hr cultivation, whereas after 96-hr, cordycepin production was decreased.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.217-220
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• 2004

The effect of media composition and culture condition on mycelial growth and cordycepin (3'-deoxyadenosine) production was determined using Cordyceps spp. Among the strains of C. militaris and C. sinensis tested, C. militaris KCTC 6862, C. militaris DGUM 32003 and C. militaris KCTC 16932 were excellent for the production of cordycepin. The optimal temperature and pH for production of cordycepin were $24^{\circ}C$ and pH ranged from 6.0 to 10, respectively. Among various sources of carbon and nitrogen tested, glucose and tryptone were very excellent for the production of cordycepin, respectively. After 5days cultivation with 1% of tryptone with nitrogen source, 39mg/l of cordycepin was produced. However, addition of phosphorus sources reduced the production of cordycepin.

• Biomedical Science Letters
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• v.15 no.4
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• pp.273-279
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• 2009

Cordycepin (3'-deoxyadenosine) is an adenosine analogue isolated from Cordyceps militaris, and it has been used as an anti-cancer and anti-inflammation ingredient in traditional Chinese medicine. We investigated the effects of cordycepin on human platelet aggregation induced by thapsigargin, and determined the cytosolic free $Ca^{2+}$ levels ($[Ca^{2+}]_i$), an aggregation-stimulating factor. Cordycepin significantly inhibited thapsigargin-induced platelet aggregation. Its inhibitory effect was continually sustained at the maximal aggregation concentration of thapsigargin. The thapsigargin-induced $[Ca^{2+}]_i$ were clearly reduced by cordycepin in the presence of exogenous $CaCl_2$ or extracellular $Ca^{2+}$-chelator (EDTA). These results suggest that cordycepin inhibited thapsigargin-induced $Ca^{2+}$-influx from extracellular domain and thapsigargin-induced $Ca^{2+}$-mobilization from intracellular $Ca^{2+}$ storage. Accordingly, our data demonstrated that cordycepin may have a beneficial effect on platelet aggregation-mediated thrombotic diseases by inhibiting a $[Ca^{2+}]_i$-elevation.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.84-90
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• 1994

Kinetic parameters of various substrates and inhibitors were measured to elucidate the binding requirements of the active site of intracellular adenosine deaminase (ADA) in Aspergillus oryzae. 3'-Deoxyadenosine was the best substrate according to the value of relative kcat/$K_m$. Purine riboside was found to be the strongest inhibitor with the $K_i$ value of $3.7{\times}10^{-5}$M. Adenine acted neither as a substrate nor as an inhibitor, suggesting the presence of ribose at N-9 of adenosine was crucial to binding. ADA also catalyzed the dechlorination of 6-chloropurine riboside, generating inosine and chloride ions. Substrate specificity of 6-chloropurine riboside was 0.86% of adenosine. Purine riboside, a competitive inhibitor of ADA, inhibit the dechlorination with similar $K_i$ value, suggesting that the same binding site was involved in deamination and dechlorination. Among the sulfhydryl group reagents, mercurials, pchloromercuribenzoate (PCMB), mersalyl acid and $HgCl_2$ inactivated the enzyme. Mersalyl acid-inactivated ADA was reactivated by thiol reagents, but PCMB-inactivated enzyme was not. When ADA was treated with the mercurial reagents, the inhibition constants and inhibition patterns were determined. Each inhibition was competitive with substrate. The $K_i$ values of these mercurial reagents were lower in 10 mM phosphate buffer than in 100 mM phosphate buffer, showing phosphate dependency.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.986-990
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• 2006

As key nucleoside intermediates for the preparation of cyclic adenosine diphosphate ribose (cADPR, 1) analogues, 8-alkyl-2' (or 3')-azido(or amino)-adenosine derivatives (16-19) were successfully prepared by alkylating selectively protected adenosine derivatives (12, 13) via Pd(0) catalyzed cross-coupling reaction with tetraalkyltin reagents, followed by the sugar modification of these 8-alkyl-adenosine derivatives according to our precedent procedure. Compared to other precedent procedures, our 8-alkylation methodology using selectively TBDMS-protected 8-alkyl adenosine derivatives as starting materials will be utilized very conveniently to prepare highly functionalized adenosine analogues, which will be serve as key intermediates for the cADPR.